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US 12,444,462 B2Granted
Electro-optical high bandwidth ultrafast differential RAM
AssigneeUniversity of Southern California
InventorsAjey Poovannummoottil Jacob, Akhilesh Ramlaut Jaiswal, Ramesh Kudalippalliyalil, Sujith Chandran
Life of this patent
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Abstract
An electro-optic random-access memory enables (1) ultra-fast write and read operation (2) featuring differential sensing (3) wavelength, and polarization multiplex high bandwidth memory access (4) enables very large-scale memory array for wafer scale ICs.
Claims47
A LEO-RAM cell comprising:
- a first ring resonator R1 that couples a first waveguide W1 to a second waveguide W2 such that the first waveguide W1 receives a first optical signal S1,
- a second ring resonator R2 that couples a third waveguide W3 to a fourth waveguide W4 such that the third waveguide W3 receives a second optical signal S2;
- a first phototransistor T1 having a base (or gate) coupled to an output of the second ring resonator R2 through the third waveguide W3 and is configured to operate the first ring resonator R1 wherein the first ring resonator R1 is configured to operate at a first resonant wavelength λbit when the first phototransistor T1 is OFF such that light output appears at a drop port of the first ring resonator R1 thereby switching second phototransistor T2 “ON” and configured to operate at non-resonant for λbit when the first phototransistor T1 is “ON” such that second phototransistor T2 turns “OFF”;
- and
- a second phototransistor T2 having a base (or gate) coupled to an output of the first ring resonator R1 through the second waveguide W2 and is configured to operate the second ring resonator R2;
- wherein the second ring resonator R2 is configured to operate at same resonant wavelength λbit when the second phototransistor T2 is “ON” such that when second ring resonator R2 is at resonance, no light will transfer to first phototransistor T1.
3 more elements
An O-SRAM cell comprising:
- a first ring resonator R1 having a first ring resonator drop-port that represents a state Q*;
- a second ring resonator R2 having a second ring resonator drop-port that represents a state Q;
- a first photodiode D1 that controls the first ring resonator R1 through first waveguide W1;
- wherein the ON state of first photodiode D1 implies that first ring resonator R1 is resonant to an input light having wavelength λbit thereby transferring maximum optical power to the first ring resonator drop-port;
- and
- a second photodiode D2 that controls the second ring resonator R2 through a second waveguide W2, wherein the ON state of second photodiode D2 implies that the second ring resonator R2 is resonant to the input light having wavelength λbit thereby transferring maximum optical power to the second ring resonator drop-port.
3 more elements
Dependencies are inferred from the claim text.